SERC Data Table of Contents

meta key # modl012
dataset or series of data Reach File Version 1 (RF1) stream map and stream topology, Chesapeake Bay watershed
keywords GIS, hydrology, rivers, modeling, water quality
originator U.S. Environmental Protection Agency
file format ARC/INFO line coverage
platform Windows NT
study site locale Chesapeake Bay Watershed, USA
beg. date (yyyymmdd) acquired 199603
ongoing? no
end date (yyyymmdd)  
meas. freq.  
site size 1671 arcs
# of stations  
west long. -80.633
east long. -74.58
north lat. 43.055
south lat. 36.602
parameters >80 reach attributes, including: basin name, cataloging unit, segment, marker index, reach length, reach type, reach name, latitude, longitude, mean annual flow, 7Q10 low flow, flow velocity
current sharing status publicly available at
current advertising status advertised by originator
abstract The U.S. Environmental Protection Agency's (EPA) Reach Files are a series of hydrographic databases of the surface waters of the continental United States and Hawaii. The structure and content of the Reach File databases were created to establish hydrologic ordering, to perform hydrologic navigation for modeling applications, and to provide a unique identifier for each surface water feature, i.e., reach codes. A key characteristic of the Reach Files are their attributes which define the connected stream network. These attributes provide connectivity regardless of the presence or absence of topologic continuity in the digital linework. Flow direction is inherent in the connectivity attributes. This attribute-level connectivity enables the Reach Files to provide hydrologic ordering of stream locations using reach codes (what is upstream and downstream of a given point in the stream network) as well as network navigation proceeding in either the upstream or downstream direction. The source for RF1 was the U.S. Geological Survey's (USGS) 1:250,000 scale hydrography that had been photo-reduced to a scale of 1:500,000 by the National Oceanic and Atmospheric Administration (NOAA). RF1 consists of approximately 68,000 reach segments comprising 650,000 miles of team. []
additional documentation / reference article and

Last Updated on 12/28/00
By Michelle Berger